US-Russian relations have been dominated by two major trends over the past few years: the vast rise in US oil output and the biggest increase in tensions between the two countries since the cold war over the Ukraine crisis.

So it might seem odd to discover that US imports of Russian crude oil in the past two months have averaged their highest level in three years.

Ship-tracking data shows that in June and July the US imported more than 70,000 barrels a day of Russian crude on average. This is the first time imports have hit that level in two consecutive months since 2012. In total, more than 4.6m barrels of Russian oil have arrived at US refineries over this period....................